cr125 offroad kart

[bkrider113]

Hi my name is joe and am building an offroad go kart but I need some help. I'm getting a tired cr125 mostly for the engine, but have the whole bike. My question is has anyone used the swing arm and rear suspension setup from a dirtbike to a kart. I know i cant use the drive setup but maybe weld or bolt some bearing hangers to the swing arm? I'm still in the planning stage and would like to have atleast rear suspension. Also was wondering if a front brake setup is going to be necesary..... PS better get used to me posting for the next year or so with more questions

thanks

 

[88s10Durango]

I haven`t started my Off Road kart yet , but if you look at a Quad they use somewhat narrow swingarm on the rear ,, it should work , only problem I see is if one tire hits a high spot on one side I think it would force the other side to do the same to a degree , thus the kart not staying level going over obstacles to mayby , might get quite a bit of tippy feeling like a trike , I want to try and do mine independent on the rear like this pic ,, I`m useing a 81 Honda 185 cc in mine , lol ,, Bill

 

[Kaptain Krunch]

I would honestly rethink using a cr125 for an offroad kart. Have you ever ridden a 125 2 stroke? they have almost no bottom end and all top, and for offroad thats not what you want.

 

[88s10Durango]

KaptainCrunch , I did copy the pics , I haven`t started my kart yet , I said I wanted to use a suspension like the ones in the pics , thought I could pass them onto bkrider113 so he could get a idea of suspension , I like the way that suspension is setup , aren`t we all here to help one another ? Personally I think bkrider113 should use a 4 stroke bike engine of a larger displacement , I have a 185cc 4 stroke in my shed I`ll be using , its off a Honda trike , It may be to small but its all I could find here without paying a ridiculous amount , he`s probably in the same shoes , lol , sorry if you misunderstood me putting the pics up ,, Bill

 

[Speedy]

I maybe getting a 125cc 4stroke, so I will watch this thread closely

 

[Kaptain Krunch]

KaptainCrunch , I did copy the pics , I haven`t started my kart yet , I said I wanted to use a suspension like the ones in the pics , thought I could pass them onto bkrider113 so he could get a idea of suspension , I like the way that suspension is setup , aren`t we all here to help one another ? Personally I think bkrider113 should use a 4 stroke bike engine of a larger displacement , I have a 185cc 4 stroke in my shed I`ll be using , its off a Honda trike , It may be to small but its all I could find here without paying a ridiculous amount , he`s probably in the same shoes , lol , sorry if you misunderstood me putting the pics up ,, Bill

Its no big deal, i dont care i wasnt getting pissed at you or anything, just came to mind when i saw it.

But yea a 250 4 stroke would be perfect for a small 1 seater in my opinion.

 

[theo]

250 would be a good engine. Mine has a 200 honda trike engine in it and it's ok, would like to have some more hp. but it will climb a wall with the high and low trans.

theo

 

[Speedy]

250 would be a good engine. Mine has a 200 honda trike engine in it and it's ok, would like to have some more hp. but it will climb a wall with the high and low trans.

theo

is that picture yours? could you direct use to your original build topic of it.

maybe some of my questions will be answered their.

 

[motor_head]

i like swingarm rear suspension don't like the body roll of independent like if you go sideways a bit on a steep hill

 

[bkrider113]

I know what you guys mean im pretty good with engines and mechanics. I know a cr125 is going to be faster than any other 125 4 stroke. I'll just have to keep the revs high, and some clutch feathering and ill be good. But i think im pretty sure im going to hardtail because it simplifies the whole kart so much more. thx for the replys

 

[zero1dhd]

I haven`t started my Off Road kart yet , but if you look at a Quad they use somewhat narrow swingarm on the rear ,, it should work , only problem I see is if one tire hits a high spot on one side I think it would force the other side to do the same to a degree , thus the kart not staying level going over obstacles to mayby , might get quite a bit of tippy feeling like a trike , I want to try and do mine independent on the rear like this pic ,, I`m useing a 81 Honda 185 cc in mine , lol ,, Bill

Standard quad rear end is fine. You don't get a tippy feeling at all. The rear doesn't articulate as you think it does, there is no angle involved at all, it's always parallel to the ground it just depends if it's up or down. As far as the complexity goes I would definitely go with a solid rear end with suspension rather than going independent. The fixed rear axle is also a lot more fun in the dirt for pitching it sideways action. Independent want to grab and flip more easily in that situation. It really depends on if you wanna go crazy rock crawling in which case you should setup a 4-wheel drive with the independent, or if you wanna go balls to the wall hauling a** down dirt roads, then go with the solid rear axle.

IF you guys need any pointers on this, I just got done building this exact kart with a 4-stroke 125 in it. See my Go-Quad thread in this forum. I even just got done with a step by step instruction set to modify a quad into a kart (or buggy if you wanna get technical cause it has suspension)

 

[theo]

Independent suspension on the rear is much better then a swing arm.

I have built karts with both, the swing axle works great but the independent kart has a much better ride and giving the same shocks, faster and more controllable at high speeds. Dual rear a arms are even better, but more costly to build.

theo

 

[modelengineer]

And you shouldn't jump a swingarm kart because if you land on 1 wheel (most jumps do, unless they are absolutely perfect, you put a LOT of stress put on the rear suspension mount and swingarm.

 

[bkrider113]

loving the feedback guys. I think im going to have no suspension though unless you guys can convince me its not that hard to fabricate a solid axle suspension setup. The hardest part for me is the swing arm bushings keeping the chain taught and shock mounting/placing
yea i know i have ****ty grammer and spelling sorry........ does anyone know the chain size/pitch for a late 80's early 90's cr125???? and any opinions if i need a front brake system for this kart????

any ideas??????

 

[Kaptain Krunch]

Front brakes arent needed, and i personally wouldnt do suspension, just get a comfy seat. A 80s or 90s cr would probably have a 520 chain, thats what my 83 rm125 has.